Caption: Taikonaut on Mars. Computer artwork of a taikonaut (Chinese astronaut) exploring near two manned Martian bases. Mars is a rocky desert world with no surface water and a gravity about one third of that on Earth. The atmosphere is mostly carbon dioxide and surface temperatures are well below freezing. Human missions to explore Mars have been planned since the 1950s, but as of 2015 none have come to fruition and current plans have been scaled back or cancelled.